Strawberries are easy to grow in containers. Peat-free multipurpose compost is a good choice. Suitable containers include grow bags, hanging baskets, troughs and tubs. Healthy productive plants are sadly difficult to achieve in the traditional strawberry pot.
Container cultivation avoids the build-up of soil problems, but vine weevil control is often essential. See the problems section below for further detail.
Strawberries grown in a heated greenhouse can produce fruit as early as mid-March, although for high quality and well-coloured fruit it is better to aim for harvest about a month later.
Suitable cultivars for forcing under glass include ‘Cambridge Favourite' AGM, ‘Honeoye' AGM, ‘Rosie’, ‘Royal Sovereign' and ‘Tamella'.
For March harvesting, bring container plants into the greenhouse in mid-December, but give no heat or water until the first new leaves appear, except for spraying with a fine mist of water on sunny days. During early growth, keep the atmosphere moist and restrict ventilation to sunny days when it is necessary to avoid overheating. Increase watering as the foliage develops.
At the end of December, start to give gentle heat and keep the night temperature at about 7-10°C (45-50°F). Too much heat will result in excessive foliage at the expense of flowers.
In February when the flowers open, increase the temperature to 15°C (60°F) and give ventilation during the day, although generally maintaining a moist atmosphere except at pollination time. Hand pollinate daily with a soft paintbrush to ensure good setting and fruit shape.
When the fruit has set, increase the temperature to 18°C (65°F). For the highest quality fruit, thin the flowers by removing the smallest ones immediately after the petals have fallen, leaving 8-10 fruits to mature.
Reduce ventilation and keep the atmosphere thoroughly moist at all times until ripening begins. Water copiously and spray with water frequently in sunny weather to promote large fruits and discourage mildew. As the fruit colours increase ventilation, reduce watering and stop spraying with water altogether to reduce the risk of fruit rot.
Apply a half-strength liquid feed every 10-14 days until the fruit begins to colour. Too much feeding will result in soft, tasteless fruit and increase the risk of rotting. The fruit should be ready to pick after mid-March.
- Bring containers into the greenhouse in early January
- Start gentle heat about three weeks later, maintaining a night temperature of 4-8°C (40-45°F) until flower trusses begin to appear in February, then raise it to 10°C (50°F)
- Hand pollinate as described above and follow the same watering and feeding regimes
- After petal fall, increase the temperature to 13°C (55°F). Once ripening begins a lower temperature will improve colour and flavour but slow down the ripening process
- Fruit should be ready for picking from mid April
For late April to early May harvesting, bring plants into an unheated greenhouse in February, and follow the steps for April harvesting.